Dispersion of the second harmonic generation in GaNxAs1−x (x = 0.25, 0.5, 0.75) alloys

The all-electron full-potential linearized augmented plane wave method has been used for an ab initio theoretical study to investigate the effect of vary the concentration of nitrogen on the second harmonic generation (SHG) of GaNxAs1−x (x = 0.25, 0.5, 0.75) alloys. Based on the density functional theory the nonlinear optical susceptibilities (NLO) namely the SHG are calculated and their spectra are analyzed. We find that reducing N concentration leads to reduce the energy band gap resulting in enhancing the functionality of GaNxAs1−x alloys and hence increasing the second-order susceptibility. A surprising finding is a nonlinear relationship between the composition and the absorption/emission energies, leading to significantly enhancing the properties not obtainable from the parent GaAs and GaN binary systems.